A photoelectric scanning technique in which a position sensor detector mounted on the receiver measures the angle of light as it bounces off the target and uses this information to suppress backgrounds beyond a specified distance.

A photoelectric scanning technique in which a beam of light shines directly from the transmitter to the receiver. An object is detected when it passes between transmitter and receiver and blocks the beam of light.

A photoelectric scanning technique that uses special filters to absorb glare and reduce or eliminate reflections. Polarized scans filter out all unwanted light sources and detect only depolarized light.

An ultrasonic mode of operation in which sound waves are transmitted toward a reflector and bounce back to a receiver. An object is detected when it passes between the sensor and reflector and blocks the sound waves.

A photoelectric scanning technique in which a beam of light shines directly from the transmitter to the receiver. An object is detected when it passes between transmitter and receiver and blocks the beam of light.